Definition: How quickly you can exhale or breathe air out of the lungs. Over time, it is a measure of how well your asthma is controlled. Peak expiratory flow rate is measured with a peak flow meter.
Also Known As: PEFR or peak flow
Peak Expiratory Flow Rate Definition
From Pat Bass, former About.com Guide
Updated February 25, 2009
About.com Health's Disease and Condition content is reviewed by the Medical Review Board
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